U.S. Pat. No. 5,039,871 issued 13 Aug. 1991 to W. E. Engeler, entitled "CAPACITIVE STRUCTURES FOR WEIGHTED SUMMATION AS USED IN NEURAL NETS" and assigned to General Electric Company is incorporated herein by reference. U.S. Pat. No. 5,039,870 issued 13 Aug. 1991 to W. E. Engeler, entitled "WEIGHTED SUMMATION HAVING DIFFERENT-WEIGHT RANKS OF CAPACITIVE STRUCTURES" and assigned to General Electric Company is incorporated herein by reference. These patents explain in their backgrounds of invention the desirability of using weighted summation networks in neural network layers, which weighted summation networks use capacitive elements to determine in accordance with Coulomb's Law the weighting accorded their synapse input signals. Y. P. Tsividis and D. Anastassion in a letter "Switched-Capacitor Neural Networks" appearing in ELECTRONICS LETTERS, 27th Aug. 1987, Vol. 23, No. 18, pages 958,959 (IEE) describe a switched capacitor method of implementing weighted summation in accordance with Coulomb's Law that is useful in analog sampled-data neural net systems. U.S. Pat. Nos. 5,039,870 and 5,039,871 describe methods of implementing weighted summation in accordance with Coulomb's Law that do not require capacitors to be switched.
It not only is desirable to use capacitive elements to determine in accordance with Coulomb's Law the weighting accorded analog synapse input signals, as described specifically in U.S. patent applications Ser. Nos. 366,838 and 366,839, it is desirable to use capacitive elements to determine in accordance with Coulomb's Law the weighting accorded digital synapse input signals. U.S. patent application Ser. No. 546,970 filed 1 Aug. 1990 by W. E. Engeler, entitled "NEURAL NETS SUPPLIED DIGITAL SYNAPSE SIGNALS DIGITAL ON A BIT-SLICE BASIS" and assigned to General Electric Company describes digital synapse input signals being so weighted. So does U.S. patent application Ser. No. 628,257 filed 14 Dec. 1990 by W. E. Engeler, entitled "DIGITAL CORRELATORS INCORPORATING ANALOG COMPUTER STRUCTURES OPERATED ON A BIT-SLICED BASIS" and assigned to General Electric Company.